- Fifteen US Congress members are trying to block a joint Rio Tinto and BHP Billiton $US6 billion ($7.7 billion) copper mine expansion in Arizona, because indigenous Apaches claim the construction would affect sacred land.
Legislation tabled in the US House of Representatives last week seeks to undo a land swap law passed in December. It gave a green light for the Rio-led joint venture Resolution Cooper to take over 980 hectares of federally protected public land at the Tonto National Forest in southeast Arizona in exchange for parcels of other conservation property.
Local tribes from the Oak Flat camp ground have been protesting against the land swap and have won support for their fight against Rio and BHP from US representative Raúl M Grijalva, the left-leaning Democrat Party's most senior member of the House of Representatives natural resources committee. He tabled legislation on Thursday, saying the "unpopular corporate giveaway" must be repealed.
"Congress shouldn't be in the business of helping big corporations at others' expense, and it certainly shouldn't break faith with Native American communities," said Mr Grijalva, who represents the state of Arizona.
Rio, including chief executive Sam Walsh, has been trying to reach a compromise with the San Carlos Apache Tribe since a decade ago when it began pushing for the land exchange to expand the mine.
Resolution Copper, a 55-45 Rio-BHP joint venture, said it was disappointed that mining opponents have pressured members of Congress to introduce legislation to block the mine in Superior, Arizona.
"The Resolution Copper mine will support 3700 jobs, generate over $US60 billion in economic impact and result in nearly $US20 billion in state and federal tax payments – Representative Grijalva's legislation puts these economic benefits at risk," the company said.
"The land-exchange legislation that passed last year was sponsored by a bipartisan majority of the Arizona delegation and passed the House and Senate by strong bipartisan margins as part of a package of over 80 land related bills."
The land exchange was tacked on to a $US585 billion bipartisan defence spending bill in December just before crucial Pentagon funding was due to expire.
Resolution Copper has an inferred mineral resource of 1737 tonnes and could be mined for more than 40 years. The first shaft has been completed at the site and about $US1 billion is being spent on exploratory activities.
The project still needs to pass a range of environmental approvals and receive the final go-ahead from the boards of Rio and BHP. If the project goes ahead, it will be up and running in about seven to 10 years.
In order to thwart the mine expansion, the proposed legislation would need to clear policy committees and win a majority in both chambers – an uphill battle. Rio has the strong backing of Arizona senator and former US presidential candidate John McCain, who has accused the mining opponents of trying to deprive the community of economic benefits.
"I am disappointed but not surprised that longtime mine opponents are trying to stop the project and kill the thousands of jobs and billions in economic activity it is set to create," Senator McCain said.
"It does not involve any tribal land or federally designated 'sacred sites', as the Interior Department's 1955 Public Land Order on Oak Flat camp ground clearly shows."
The proposed mine is next to the Apache Leap, a site regarded as sacred because legend has it Apache warriors leaped to their deaths to avoid capture from US cavalry.
Rio is required to undergo a full environmental impact study on the mine before the land is transferred to the mine. The Apache Leap cliffs will be a designated special management area.
The Apache leadership has largely avoided dialogue with Resolution Copper about the mine, instead opting to pressure federal lawmakers.
The House of Representatives bill tabled last week was co-sponsored by Republicans Tom Cole, Markwayne Mullin and Walter Jones, as well as Democrats Betty McCollum, Norma Torres, Patrick Murphy, Alcee Hastings, Ben Ray Lujan, Raul Ruiz, Tony Cardenas, Xavier Becerra, Jared Polis, Ruben Gallego and Gwen Moore.
Mr Grijalva has a history of fighting for native Americans.
In 2010 he introduced the RESPECT Act, mandating that federal agencies consult native tribes before taking major actions.